Ink delivery systems are utilized by various types of printers to generate text and/or images on a printing medium, such as paper, normally in response to communications and/or control signals from a computer. One known type of ink delivery system includes a printhead assembly that is configured to slide along a shaft in response to communications and/or control signals from a computer. As the printhead assembly slides along the shaft, ink is ejected through nozzles disposed in the printhead assembly onto the print medium to generate the text and/or images. The printhead assembly is said to be positioned “on-axis” because it is coupled to the shaft. While the printhead assembly may have one or more integral ink reservoirs (one per color), the primary bulk supply of ink is located in one or more ink supply containers (one per color) located somewhat remote from the shaft and printhead (though still within the printer), which is referred to as “off-axis” positioning. Typically, the printer includes a plurality of off-axis ink supply containers, each containing a different color or type of ink. The ink supply containers are connected to the printhead assembly by tubes, which provide fluid communication between the ink supply containers and the printhead assembly. Ink is supplied from the ink supply containers through the respective tubes to the printhead assembly at various times.
With such ink delivery systems, there is a desire to reduce or prevent air accumulation in various parts of the printhead assembly, because an over-accumulation of air in the printhead assembly can degrade the printing quality and/or reduce the usable life of the printhead assembly. There is a further desire to reduce or prevent water evaporation through the nozzles, for example, during long duration storage, because such may leave accretions in the nozzle bore made up of the non-volatile ink components. Another desire is to reduce or prevent obstructions, including kinks, in the tubes connecting the off-axis ink supply containers to the printhead assembly.
The embodiments described hereinafter were developed in light of these and other desires.